diff --git a/ChangeLog b/ChangeLog
index 9f5208301e..f03c3cc0c2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,6 @@
-Thu Jan 29 14:08:59 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Thu Jan 29 14:12:15 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* configure.in (BASERUBY): erases RUBYOPT at the test.
 
 	* configure.in (OBJCOPY): not used on Windows.
 
diff --git a/configure.in b/configure.in
index 66b5e91c25..a5b95704f4 100644
--- a/configure.in
+++ b/configure.in
@@ -18,7 +18,7 @@ AC_ARG_WITH(baseruby,
 	[
 		BASERUBY="ruby"
 	])
-test "`$BASERUBY -e 'p 42' 2>/dev/null`" = 42 ||
+test "`RUBYOPT=- $BASERUBY -e 'p 42' 2>/dev/null`" = 42 ||
     BASERUBY="echo executable host ruby is required.  use --with-baseruby option.; false"
 AC_SUBST(BASERUBY)